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[unix-history] / usr / src / usr.bin / lex / yylex.c

/* yylex - scanner front-end for flex */

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Vern Paxson of Lawrence Berkeley Laboratory.
* 
* The United States Government has rights in this work pursuant
* to contract no. DE-AC03-76SF00098 between the United States
* Department of Energy and the University of California.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#ifndef lint
static char sccsid[] = "@(#)yylex.c     5.2 (Berkeley) 6/18/90";
#endif /* not lint */

#include <ctype.h>
#include "flexdef.h"
#include "parse.h"


/* ANSI C does not guarantee that isascii() is defined */
#ifndef isascii
#define isascii(c) ((c) <= 0177)
#endif


/* yylex - scan for a regular expression token
*
* synopsis
*
*   token = yylex();
*
*     token - return token found
*/

int yylex()

   {
   int toktype;
   static int beglin = false;

   if ( eofseen )
       toktype = EOF;
   else
       toktype = flexscan();

   if ( toktype == EOF || toktype == 0 )
       {
       eofseen = 1;

       if ( sectnum == 1 )
           {
           synerr( "premature EOF" );
           sectnum = 2;
           toktype = SECTEND;
           }

       else if ( sectnum == 2 )
           {
           sectnum = 3;
           toktype = 0;
           }

       else
           toktype = 0;
       }

   if ( trace )
       {
       if ( beglin )
           {
           fprintf( stderr, "%d\t", num_rules + 1 );
           beglin = 0;
           }

       switch ( toktype )
           {
           case '<':
           case '>':
           case '^':
           case '$':
           case '"':
           case '[':
           case ']':
           case '{':
           case '}':
           case '|':
           case '(':
           case ')':
           case '-':
           case '/':
           case '\\':
           case '?':
           case '.':
           case '*':
           case '+':
           case ',':
               (void) putc( toktype, stderr );
               break;

           case '\n':
               (void) putc( '\n', stderr );

               if ( sectnum == 2 )
                   beglin = 1;

               break;

           case SCDECL:
               fputs( "%s", stderr );
               break;

           case XSCDECL:
               fputs( "%x", stderr );
               break;

           case WHITESPACE:
               (void) putc( ' ', stderr );
               break;

           case SECTEND:
               fputs( "%%\n", stderr );

               /* we set beglin to be true so we'll start
                * writing out numbers as we echo rules.  flexscan() has
                * already assigned sectnum
                */

               if ( sectnum == 2 )
                   beglin = 1;

               break;

           case NAME:
               fprintf( stderr, "'%s'", nmstr );
               break;

           case CHAR:
               switch ( yylval )
                   {
                   case '<':
                   case '>':
                   case '^':
                   case '$':
                   case '"':
                   case '[':
                   case ']':
                   case '{':
                   case '}':
                   case '|':
                   case '(':
                   case ')':
                   case '-':
                   case '/':
                   case '\\':
                   case '?':
                   case '.':
                   case '*':
                   case '+':
                   case ',':
                       fprintf( stderr, "\\%c", yylval );
                       break;

                   default:
                       if ( ! isascii( yylval ) || ! isprint( yylval ) )
                           fprintf( stderr, "\\%.3o", yylval );
                       else
                           (void) putc( yylval, stderr );
                       break;
                   }
                       
               break;

           case NUMBER:
               fprintf( stderr, "%d", yylval );
               break;

           case PREVCCL:
               fprintf( stderr, "[%d]", yylval );
               break;

           case EOF_OP:
               fprintf( stderr, "<<EOF>>" );
               break;

           case 0:
               fprintf( stderr, "End Marker" );
               break;

           default:
               fprintf( stderr, "*Something Weird* - tok: %d val: %d\n",
                        toktype, yylval );
               break;
           }
       }
           
   return ( toktype );
   }